(1) Field of the Invention
This invention relates to water treatment, and more particularly to feeders for introducing treatment chemicals into a recirculating water stream from a swimming pool or the like.
(2) Brief Description of the Art
If untreated, swimming pool water provides an hospitable forum for the growth of bacteria, algae, and other undesirable and potentially unhealthful organisms. It, accordingly, has become common practice to treat pool water on both periodic and continuous bases with treatment chemicals to kill/control such organisms.
Such treatment is typically undertaken via the introduction of chlorine into the pool water at levels effective to kill or control the unwanted organisms. The chlorine source may be in liquid form or may be in a solid form which is then dissolved in the pool water. Among solid sources of chlorine are calcium hypochlorite (cal hypo), dichloroisocyanuric acid (dichlor), and trichloroisocyanuric acid (trichlor).
A variety of feeders exist to deliver chlorine from solid chemical tablets and the like. It is known to utilize a floating erosion dispenser, also known as a “floater” or “feeder”, to provide a continuous release of the chemical. The floater contains the solid chemical and provides a controlled exposure of the chemical to the pool water which in turn controls the speed with which the water erodes the solid chemical to introduce chlorine to the pool water. Exemplary floaters are disclosed in U.S. Pat. No. 4,917,868 and U.S. Design Pat. Nos. 297,857 and 309,493. It is also known to pump pool water through an external feeder which may be incorporated in a circulation system that also provides filtering of the pool water. Among such systems are intermittent spray systems, erosion systems, and partial periodic immersion systems. Examples of such systems are shown in U.S. Pat. Nos. 5,932,093, 5,928,608, 5,441,711, 5,427,748, 5,419,355, 5,384,102, 5,133,381, and 4,208,376, and U.S. Reissue Pat. No. 33,861. As additional background, U.S. Pat. Nos. 5,112,521 and 5,004,549 disclose various solid calcium hypochlorite compositions.
Obtaining proper dissolution of the treatment chemical and avoiding undesirable deposits or residues have posed problems in feeder design. Particular problems exist with the use of commercial calcium hypochlorite pellets which produce calcium carbonate deposits. See e.g., U.S. Pat. No. 6,045,706.